1. Field of the Invention
The present invention relates to the management of mobile end systems in a packet switched data network that provides computer users with remote access to the internet and to private intranets using virtual private network services over a high speed, packet switched, wireless data link. In particular, the invention relates to the management of connection handovers when a mobile end system moves from one cell to another.
2. Description Of Related Art
FIG. 1 depicts three business entities, whose equipment, working together typically provide remote internet access to user computers 2 through user modems 4. User computers 2 and modems 4 constitute end systems.
The first business entity is the telephone company (telco) that owns and operates the dial-up plain old telephone system (POTS) or integrated services data network (ISDN) network. The telco provides the media in the form of public switched telephone network (PSTN) 6 over which bits (or packets) can flow between users and the other two business entities.
The second business entity is the internet service provider (ISP). The ISP deploys and manages one or more points of presence (POPs) 8 in its service area to which end users connect for network service. An ISP typically establishes a POP in each major local calling area in which the ISP expects to subscribe customers. The POP converts message traffic from the PSTN run by the telco into a digital form to be carried over intranet backbone 10 owned by the ISP or leased from an intranet backbone provider like MCI, Inc. An ISP typically leases fractional or full T1 lines or fractional or full T3 lines from the telco for connectivity to the PSTN. The POPs and the ISP""s medium data center 14 are connected together over the intranet backbone through router 12A. The data center houses the ISP""s web servers, mail servers, accounting and registration servers, enabling the ISP to provide web content, e-mail and web hosting services to end users. Future value added services may be added by deploying additional types of servers in the data center. The ISP also maintains router 12A to connect to public internet backbone 20. In the current model for remote access, end users have service relationships with their telco and their ISP and usually get separate bills from both. End users access the ISP, and through the ISP, public internet 20, by dialing the nearest POP and running a communication protocol known as the Internet Engineering Task Force (IETF) point-to-point protocol (PPP).
The third business entity is the private corporation which owns and operates its own private intranet 18 through router 12B for business reasons. Corporate employees may access corporate network 18 (e.g., from home or while on the road) by making POTS/ISDN calls to corporate remote access server 16 and running the IETF PPP protocol. For corporate access, end users only pay for the cost of connecting to corporate remote access server 16. The ISP is not involved. The private corporation maintains router 12B to connect an end user to either corporate intranet 18 or public internet 20 or both.
End users pay the telco for the cost of making phone calls and for the cost of a phone line into their home. End users also pay the ISP for accessing the ISP""s network and services. The present invention will benefit wireless service providers like Sprint PCS, PrimeCo, etc. and benefit internet service providers like AOL, ATandT Worldnet, etc.
Today, internet service providers offer internet access services, web content services, e-mail services, content hosting services and roaming to end users. Because of low margins and no scope of doing market segmentation based on features and price, ISPs are looking for value added services to improve margins. In the short term, equipment vendors will be able to offer solutions to ISPs to enable them to offer faster access, virtual private networking (which is the ability to use public networks securely as private networks and to connect to intranets), roaming consortiums, push technologies and quality of service. In the longer term, voice over internet and mobility will also be offered. ISPs will use these value added services to escape from the low margin straitjacket. Many of these value added services fall in the category of network services and can be offered only through the network infrastructure equipment. Others fall in the category of application services which require support from the network infrastructure, while others do not require any support from the network infrastructure. Services like faster access, virtual private networking, roaming, mobility, voice, quality of service, quality of service based accounting all need enhanced network infrastructure. The invention described here will be either directly provide these enhanced services or provide hooks so that these services can be added later as future enhancements. Wireless service providers will be able to capture a larger share of the revenue stream. The ISP will be able to offer more services and with better market segmentation.
The present invention provide end users with remote wireless access to the public internet, private intranets and internet service providers. Wireless access is provided through base stations in a home network and base stations in foreign networks with interchange agreements.
It is an object of the present invention to provide a wireless packet switched data network for end users that divides mobility management into local, micro, macro and global connection handover categories and minimizes handoff updates according to the handover category. It is another object to integrate MAC handoff messages with network handoff messages. It is a further object of the present invention to separately direct registration functions to a registration server and direct routing functions to inter-working function units. It is yet another object to provide an intermediate XTunnel channel between a wireless hub (also called access hub AH) and an inter-working function unit (IWF unit) in a foreign network. It is yet another object to provide an IXTunnel channel between an inter-working function unit in a foreign network and an inter-working function unit in a home network. It is yet another object to enhance the layer two tunneling protocol (L2TP) to support a mobile end system. It is yet another object to perform network layer registration before the start of a PPP communication session.